let mysql = require('mysql'),
    connection;
class Sql{
    // constructor(){} 构造函数
    get(sql,variable,callback){
        connection   = mysql.createConnection({
            host     : '',
            user     : '',
            password : '',
            port: '3306',
            database:''
        });
        connection.connect();
        connection.query(sql,variable, (err,result) => {
            callback(err, result);
        });
        connection.end();
    }
}
module.exports = Sql;